function [res] = isnumber(in)
% return array res length of in array, where in is supposed to be a character array
%
if(isempty(in))
   res = 0;
   return;
end;

res = zeros(length(in), 1);
if(isnumeric(in))
   res = ones(length(in), 1);
   return;
end;
if(~ischar(in))
   return;
end;
numlist = '0123456789.+-';
for i = 1:length(in)
   if(any(numlist == in(i)))
      res(i) = 1;
   end;
end;
return;
